1. Field of the Invention
The present invention relates to space transportation. More specifically, the present invention relates to space transportation nodes including tether systems.
2. Description of the Related Art
Resource recovery operations on Earth require an economic feasibility with a financial return on the invested capital. The cost of transporting payloads to and from the moon is a barrier to economic development of the moon.
Rocket propelled space vehicles transporting cargo outside the proximity of the Earth in airless space do not require the same vehicle hardware to push up through the atmosphere or land on the moon, but discarding the vehicle hardware on each mission like Apollo is still expensive. The space exploration initiative announced by President Bush and implemented by NASA has the opportunity to mature the transportation cycles beyond the Earth and the moon. The requirements and cost for each of these six lunar transportation cycles is different and the requirements for manned versus unmanned missions differs greatly.
If one breaks out these different cycle or leg transportation requirements for each portion of a lunar trip, then six distinct transportation cycles emerge. As each cycle matures, it becomes more effective and efficient. Commerce competitive forces help accelerate this maturing process and the evolution into a cost competitive transportation environment.
The transportation cycles emerging are Earth to low Earth orbit or LEO, LEO to Lunar orbit “LO,” LO to the lunar surface, the lunar surface back to LO, LO to LEO and the re-entry from LEO to the Earth's surface. Placing a transportation node between each of the separate cycles would accelerate the maturing of the transportation process and facilitate introducing commerce. In a mature transportation cycles on Earth, we find that changing the requirements for a portion of a trip, like from water to land results in the change of a vehicle and results in a harbor emerging.
Why not fly and eliminate the harbor? Well, people fly, eliminate the harbor and pay the extra cost, but most cargo goes a different less expensive route through the harbor. The airport becomes the transportation node for humans and the harbor is for cargo with very different costs related to transportation. Aircraft manufacturers want all humans and cargo to fly, but when paying for the transportation, the cost competitive aspects become important.
In a remote site like the moon, the ratio of humans to cargo is significantly skewed. In looking at similar remote locations on Earth the ratio is less than 1% human and 99% cargo. To combine the manned and unmanned portions as we did in Apollo makes space transportation expensive, in part, because the safety and reliability of manned space flight is expensive. Such manned vehicles may be similar to the Saturn vehicle of the Apollo project, which landed the first man on the moon more than 30 years ago. The next series of exploration trips to the moon might consider separating unmanned cargo from humans in some manner consistent with safety.
Rendezvousing, docking and transferring payloads between space vehicles was performed more than forty years ago in the Apollo program, and more recently between shuttles and the International Space Station. The Apollo program used a form of transportation node, for example, the astronauts had to transfer cargo from the lunar lander to the command module in lunar orbit. The command module in lunar orbit was a node in the transportation system and saved mass from being transported to and from the moon's surface.
Today these transportation node techniques and procedures can be refined and used, for example, between each of the six transportation cycles and two of the nodes already exist, the Spaceports on Earth and the International Space Station. Travel between them has become partly commercial and will become competitive. In such conventional systems, the actual transfer of cargo is performed by people after docking of the vehicles and opening of a hatch. However, the automatic transfer of cargo between two vehicles in space, such as unmanned space vehicles, is a more complex operation, but possible by combining innovation with conventional systems. The enhancement of the transportation process to be more effective and more affordable can also happen.
U.S. Patent Application Publication No. 2002/0079407 to Lounge et al. entitled, “Underway replenishment system for space vehicles” discloses a replenishment system used to deliver payloads and supplies to an orbiting receiving space vehicle using a tether. The 2002/0079407 application does not enhance the payload movement. The 2002/0079407 application discloses a method of transferring payloads between a delivering space vehicle and a receiving space vehicle, but falls short of a transportation node.
U.S. Pat. No. 4,790,499, to Taylor, et al., describes docking with an orbital object using a tether. Docking with an object at the end of a cable is less likely to damage the orbital facility because both objects can move in rendezvous and docking operation. The '499 patent discloses a passive operations with no mention of active “seeker” tether tip operations.